A User Equipment (UE) may perform a session with a communication opposite end through a Circuit Switched (CS) domain or a Packet Switched (PS) domain: when the UE performs a session through the CS domain, a Service Centralization and Continuity Application Server (SCC AS) on a network side establishes an access leg that is based on the CS domain for the session, and the session is performed through the CS domain under the control of the access leg that is based on the CS domain; likewise, when the UE performs a session through the PS domain, the SCC AS establishes an access leg that is based on the PS domain for the session, and the session is performed through the PS domain under the control of the access leg that is based on the PS domain.
When the UE is transferred, for example, transferred from a zone controlled by the PS domain to a zone controlled by the CS domain, or transferred from a zone controlled by the CS domain to a zone controlled by the PS domain, the session of the UE also needs to be transferred. In the prior art, the UE sends a session transfer request to the SCC AS, the SCC AS establishes, according to the session transfer request, an access leg that is based on a target network for the session to be transferred, and releases an access leg of a source network, and the session is performed through the target network under the control of the access leg that is based on the target network.
In the implementation of the present invention, the inventors find that the prior art has at least the following problem. If the transferred UE has at least one session belonging to a conference, and the UE is an initiator of the conference, after the session of the UE is transferred through the method in the prior art, a problem that the conference cannot be controlled may be caused.